Sight glasses and pipes incorporating the same

Abstract

Sight glass assemblies, pipe assemblies including the same, and methods for assembling pipe assemblies are disclosed. Sight glass assemblies may include an annular body of a transparent material. The annular body may include a peripheral surface, an interior surface defining at least a portion of a fluid path, first and second parallel planar annular surfaces spaced a first distance apart, and at least one passage extending through the annular body from the first planar annular surface to the second planar annular surface between the peripheral and interior surfaces. In some examples, a sight glass assembly may include at least one spacing element, which may include first and second bearing surfaces. The first and second bearing surfaces may be spaced a second distance at least as large as the first distance. In some examples, the interior surface may be chemically resistant to at least one predetermined fluid.

1. A sight glass assembly, comprising:
 an annular body of a transparent material, the annular body comprising:
 a peripheral surface, 
 an interior surface defining at least a portion of a fluid path, 
 a first planar annular surface, 
 a second planar annular surface parallel to and spaced a first distance from the first planar annular surface, and 
 at least three passages extending through the annular body from the first planar annular surface to the second planar annular surface, wherein at least a part of each of the passages is disposed between the peripheral surface and the interior surface; and 
 
 at least three spacing elements disposed in at least three of the passages, wherein each of the spacing elements extends along one of the passages from a first bearing surface to a second bearing surface, the first bearing surface is spaced a second distance from the second bearing surface, the second distance is at least as large as the first distance, and the spacing elements comprise a material having a compressive stiffness greater than the compressive stiffness of the transparent material. 
 
   
   
     2. The sight glass assembly of  claim 1 , wherein at least one of the spacing elements comprises a cylinder extending from the first bearing surface to the second bearing surface. 
   
   
     3. The sight glass assembly of  claim 2 , wherein at least one of the passages is a hole, the cylinder is a tube extending from the first bearing surface to the second bearing surface, and the tube is configured for a slip-fit in the hole. 
   
   
     4. The sight glass assembly of  claim 3 , wherein:
 the transparent material comprises an acrylic and the material having a compressive stiffness greater than the compressive stiffness of the transparent material is metal; 
 the tube is configured to receive a bolt extending therethrough; 
 the tube has a first solid cross-sectional area in a plane corresponding to one of the first and second bearing surfaces, and the bolt has a second solid cross-sectional area in the plane corresponding to one of the first and second bearing surfaces; and 
 the first solid cross-sectional area is larger than the second solid cross-sectional area. 
 
   
   
     5. The sight glass assembly of  claim 2 , wherein the cylinder has a first diameter and an axis, first and second at least partially threaded regions extend along the axis from respective ones of the first and second bearing surfaces, the first and second threaded regions have a second diameter, and the second diameter is smaller than the first diameter. 
   
   
     6. The sight glass assembly of  claim 2 , wherein the transparent material comprises an acrylic and the material having a compressive stiffness greater than the compressive stiffness of the transparent material is metal. 
   
   
     7. A method of assembling a sight glass into a pipe assembly, the sight glass being formed of a transparent material and comprising a first annular surface, a second annular surface parallel to and spaced a first distance from the first annular surface, and a plurality of holes extending through the sight glass from the first annular surface to the second annular surface, the method comprising the following actions, but not necessarily in the order recited:
 providing a first pipe section having a first mounting flange; 
 providing a second pipe section having a second mounting flange; 
 inserting at least three spacing elements in the plurality of holes, the spacing elements each having a first bearing surface and a second bearing surface parallel to and spaced a second distance from the first bearing surface, wherein the second distance is at least as large as the first distance, wherein the spacing elements comprise a material having a compressive stiffness greater than the compressive stiffness of the transparent material, and the spacing elements have a first solid cross-sectional area in a plane corresponding to one of the first and second bearing surfaces; 
 arranging the first and second pipe sections and the sight glass with the first and second mounting flanges proximate respective ones of the first and second annular surfaces; 
 inserting a first gasket between the first mounting flange and the first annular surface; 
 inserting a second gasket between the second mounting flange and the second annular surface; 
 inserting a fastening element through the first mounting flange, one of the holes through the sight glass, and the second mounting flange, wherein the fastening element has a second solid cross-sectional area in the plane corresponding to one of the first and second bearing surfaces, and the first solid cross-sectional area is larger than the second solid cross-sectional area; and 
 tightening the fastening element to compress the first gasket between the first mounting flange and the first annular surface, compress the second gasket between the second mounting flange and the second annular surface, and secure the first and second mounting flanges to respective ones of the first and second bearing surfaces of the at least three spacing elements. 
 
   
   
     8. The method of  claim 7 , further comprising securing the spacing elements in the holes prior to arranging the first and second pipe sections and the sight glass with the first and second mounting flanges proximate respective ones of the first and second annular surfaces. 
   
   
     9. The method of  claim 7 , wherein inserting a fastening element through the first mounting flange, one of the holes through the sight glass, and the second mounting flange further comprises inserting the fastening element through one of the spacing elements. 
   
   
     10. The method of  claim 9 , wherein the transparent material comprises an acrylic and the material having a compressive stiffness greater than the compressive stiffness of the transparent material is metal. 
   
   
     11. A pipe assembly, comprising:
 a first pipe section having a first mounting flange; 
 a second pipe section having a second mounting flange; 
 at least three spacing elements, each of which has a first bearing surface and a second bearing surface parallel to and spaced a first distance from the first bearing surface; 
 a plurality of fastening elements, wherein the plurality of fastening elements secure the first and second mounting flanges to respective ones of the first and second bearing surfaces of the at least three spacing elements, wherein structural loads within the pipe assembly pass between the first and second pipe sections, and wherein the first and second mounting flanges, the spacing elements and the fastening elements carry the structural loads between the first and second pipe sections; and 
 a ring-shaped body of a transparent material disposed between the first and second mounting flanges, the ring-shaped body comprising:
 first and second annular surfaces, wherein the second annular surface is parallel to and spaced a second distance from the first annular surface, and the first distance is at least as large as the second distance, and 
 a plurality of holes extending through the ring-shaped body from the first annular surface to the second annular surface and parallel to a longitudinal axis of the ring-shaped body; 
 
 wherein at least one of the spacing elements is disposed in and extends through at least one of the plurality of holes, at least one of the fastening elements extends through one of the plurality of holes, the first and second annular surfaces are disposed proximate respective ones of the first and second mounting flanges, the spacing elements comprise a material having a compressive stiffness greater than the compressive stiffness of the transparent material, and the ring-shaped body is isolated from at least a portion of the compressive structural loads between the first and second pipe sections. 
 
   
   
     12. The pipe assembly of  claim 11 , further comprising first and second gaskets, wherein the first gasket is disposed between the first mounting flange and the first annular surface, and the second gasket is disposed between the second mounting flange and the second annular surface. 
   
   
     13. The pipe assembly of  claim 11 , wherein at least some of the spacing elements comprise a cylinder extending from the first bearing surface to the second bearing surface, and the cylinder is configured for a slip-fit in one of the plurality of holes. 
   
   
     14. The pipe assembly of  claim 11 , wherein at least some of the plurality of fastening elements comprise one of the spacing elements. 
   
   
     15. The pipe assembly of  claim 11 , wherein the ring-shaped body comprises at least three holes extending through the ring-shaped body from the first annular surface to the second annular surface and parallel to a longitudinal axis of the ring-shaped body, each of the at least three spacing elements is disposed in and extends through one of the holes, and each of the fastening elements extends through one of the holes. 
   
   
     16. The pipe assembly of  claim 11 , wherein at least a first one of the spacing elements includes a cylindrical passage extending therethrough from the first bearing surface to the second bearing surface, and one of the fastening elements extends through the cylindrical passage. 
   
   
     17. The pipe assembly of  claim 16 , wherein:
 compressive loads exist between the first and second mounting flanges; 
 a first portion of the compressive loads passes through the at least three spacing elements; 
 a second portion of the compressive loads passes through the ring-shaped body and induces compressive stresses therein; and 
 the at least three spacing elements are configured to prevent inducing compressive stresses in the ring-shaped body that are high enough to cause cracking of the ring shaped body. 
 
   
   
     18. The pipe assembly of  claim 17 , wherein substantially all of the compressive loads pass through the at least three spacing elements. 
   
   
     19. The pipe assembly of  claim 16 , wherein:
 the transparent material comprises an acrylic and the material having a compressive stiffness greater than the compressive stiffness of the transparent material is metal; 
 the first one of the spacing elements has a first solid cross-sectional area in a plane corresponding to one of the first and second bearing surfaces; 
 the fastening element extending through the cylindrical passage of the first one of the spacing elements has a second solid cross-sectional area in the plane corresponding to one of the first and second bearing surfaces; and 
 the first solid cross-sectional area is larger than the second solid cross-sectional area. 
 
   
   
     20. The pipe assembly of  claim 19 , wherein compressive loads exist between the first and second mounting flanges, a first portion of the compressive loads passes through the at least three spacing elements, a second portion of the compressive loads passes through the ring-shaped body, and the first portion of the compressive loads is larger than the second portion of the compressive loads. 
   
   
     21. The pipe assembly of  claim 11 , wherein each of the spacing elements includes a cylindrical passage extending therethrough from the first bearing surface to the second bearing surface, each of the spacing elements is disposed in and extends through one of the plurality of holes extending through the ring-shaped body, and each of the plurality of fastening elements is disposed in and extends through the cylindrical passage of one of the spacing elements. 
   
   
     22. A pipe assembly, comprising:
 a first pipe section having a first mounting flange; 
 a second pipe section having a second mounting flange; 
 at least three spacing elements, wherein each spacing element includes a first bearing surface, a second bearing surface parallel to and spaced a first distance from the first bearing surface, and a cylindrical passage extending therethrough from the first bearing surface to the second bearing surface, and each of the spacing elements has a first solid cross-sectional area in a plane corresponding to one of the first and second bearing surfaces; 
 at least three fastening elements, wherein each of the fastening elements is disposed in and extends through the cylindrical passage through one of the spacing elements, the at least three fastening elements secure the first and second mounting flanges to respective ones of the first and second bearing surfaces of the at least three spacing elements, and structural loads within the pipe assembly pass between the first and second pipe section, wherein the first and second mounting flanges, the spacing elements and the fastening elements carry the structural loads between the first and second pipe sections, each of the fastening elements has a second solid cross-sectional area in the plane corresponding to one of the first and second bearing surfaces, and the first solid cross-sectional area is larger than the second solid cross-sectional area; and 
 a ring-shaped body of a transparent material disposed between the first and second mounting flanges, the ring-shaped body comprising:
 first and second annular surfaces, wherein the second annular surface is parallel to and spaced a second distance from the first annular surface, and the first distance is at least as large as the second distance, and 
 at least three holes extending through the ring-shaped body from the first annular surface to the second annular surface and parallel to a longitudinal axis of the ring-shaped body; 
 
 wherein each of the at least three spacing elements is disposed in and extends through one of the at least three holes, the first and second annular surfaces are disposed proximate respective ones of the first and second mounting flanges, the spacing elements comprise a material having a compressive stiffness greater than the compressive stiffness of the transparent material, and the ring-shaped body is isolated from at least a portion of the structural loads between the first and second pipe sections. 
 
   
   
     23. The pipe assembly of  claim 22 , wherein compressive loads exist between the first and second mounting flanges, a first portion of the compressive loads passes through the at least three spacing elements, a second portion of the compressive loads passes through the ring-shaped body, and the first portion of the compressive loads is larger than the second portion of the compressive loads. 
   
   
     24. The pipe assembly of  claim 22 , wherein the transparent material comprises an acrylic and the material having a compressive stiffness greater than the compressive stiffness of the transparent material is metal.